Potential of Microalgae Cultivated in Wastewater for Enhancing Biodiesel Production

Abstract

The rising global demand for sustainable and environmentally friendly energy sources has intensified interest in biofuels, particularly biodiesel. Among the various feedstock’s explored for biodiesel production, microalgae have emerged as a promising alternative due to their high lipid productivity, rapid growth rates, and ability to thrive in diverse environments, including wastewater. This study explored the potential of native microalgal strains isolated from wastewater in Sokoto metropolis for biodiesel applications. Physicochemical analysis of the wastewater revealed temperature (25.3 ± 0.5 °C), biochemical oxygen demand (3.4 mg/L), electrical conductivity (3420 µS/cm), dissolved oxygen (39.51 mg/L), nitrate (0.29 mg/L), phosphate (28.65 mg/L), pH (6.27), and trace metals (Fe, Zn, Pb, Cd, Cr), all of which were within World Health Organization (WHO) permissible limits. Ten isolates were recovered through serial dilution and identified using morphological characteristics. Biomass and lipid productivity were evaluated under a 16:8 h light–dark cycle, and lipid content was quantified gravimetrically. Among the isolates, Scenedesmus sp. produced the highest biomass yield (0.224 g/L) and lipid productivity (0.57 ± 0.006 g/L/day). Statistical analysis (ANOVA) showed significant variation (p < 0.05) among isolates. The findings indicate that wastewater can serve as a low-cost medium for microalgal cultivation, simultaneously reducing nutrient discharge and treatment costs. Utilizing indigenous microalgae such as Scenedesmus sp. offers a promising strategy for sustainable biodiesel production in resource-limited settings.